ABout built in sound

'ello, i have a question about the surround sound built in on the motherboard. I have a gigabyte nForce 250 and it has built in audio(like most boards) but also has a suround sound hookup. the back of my computer has the standard audio ports, but i also have an extension and ports that connect to my MB and mount like a normal card. THis has ports that say side, subwoofer, rear R/L, rca out, and SFDIF out. do i have to hook this card up?? and one last thing, whats a good speaker surround system, for a decent price? thxs :grinthumb